The present invention relates to the rendering of overlays on maps, and in particular rendering overlays at different zoom levels.
A problem with zooming on digital maps is that features, such as text labels, icons, boundary lines, etc. overwhelm the map if they stay the same size as a user zooms in, and become less cosmetically pleasing as a user zooms out. One solution is to manually set different sizes for different zoom levels, or require the user to make an adjustment. Another solution is to change the size proportionately.
There are many examples of solutions in the prior art. Publ. 20080013792 describes a proportional variation in symbol size with zoom. RIM Pub. 20150009234 describes reducing the amount of map data transmitted to a mobile device depending on the zoom level. Polygon features that become smaller than a threshold are discarded at a certain zoom level. Polygon lines are suppressed where they overlap with or are too close to another, higher priority polyline feature. Google Pub. 20150187337 describes removing colliding labels as a map is zoomed out.
ArcGIS by ESRI includes a capability to change feature size, such as a label, so that it fits within a polygon on the map (e.g., state, county boundary) as the map is zoomed out.